Volt-ampere meter.



PATENTEDQ APR. 21, 1903.

' L. M. PIGNOLET.

VOLT AMPERE METER.

APPLICATION FILED SEPT. 27, 1901.

E0 MODEL.

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LOUIS M. PIGNOLET, OF ORANGE, NEW JERSEY.

VOLT-AMPERE METER.

SPECIFICATION forming part of Letters Patent No. 725,765, dated April21, 1903.

Application filed September 27, 1901. Serial No. 76,802. (No model.)

To all whom, it mag/concern.-

Be it known that 1, Louis M. PIGNOLET, a citizen of the United States ofAmerica, and a resident of Orange, in the county of Essex and State ofNew Jersey, have invented certain new and useful Improvements in Volt-Ampere Meters,,of which the following is a specification.

The object of my invention is to perfect the volt-ampere meter. 7

The improvements appertain particularly to the type of instrumentdepicted in full in former Letters Patent granted to myself and James J.Bradley on October 9, 1900, No. 659,506, entitled Magnetic regulator forgalvanometers. In such instruments 2. delioately swinging aluminiumneedle is employed as an index or pointer. When the current is turnedon, the needle swings to and fro like a pendulum, but does not come torest as soon as could be desired. By my present invention practically notime is lost in obtaining a reading on the scale. To this end a manualdevice is employed to stop the needle from swinging, except throughavery small are, at about the degree which one can judge to be thestopping-point, approximately.

My invention also involves means for obtaming greater accuracy in thereading by preventing influences from acting thereon.

from outside sources, such as iron and magnets. In the former patent theremedy I find is fair as far as it goes. I now construct the instrumentnot only with an iron shield under the same and contiguous to theoutside of the solenoid, but I also have been able to so construct thedevice as to practically perfect the shielding of the armature to whichthe needle is attached. I provide an iron sheet extending from the ironbase-plate, so as to cover one end of the solenoid and also thetop,where the iron sheet is on the opposite side of. the solenoid,measured from the base-plate.

My invention also includes means for increasing the certainty of readingthe higher voltages with greater accuracy. Engineers and users andmanufacturers have desired a small pocket instrument adapted to indicateas high as two hundred and fifty volts, by larger and larger movementsof the needle the higher and higher the voltage, and at the same time tohave a short range of the needle. The

device embodying my invention accomplishes this result effectually, asproved by actual tests. I provide, in combination, an armature for theneedle of such a construction that the electromagnet of the meter causesgreater and greater throws of the needle the more the poles of thearmature depart from-the poles of the permanent. magnet.

More particularly the nature of the improvement is described as follows:Heretofore in order that there be a sufficient magnetic attractionbetween the permanent magnet and the iron armature to give a positivecontrol of the armature the latter is made thick,butobjectionablyheavy.Forexample,

an armature one-half inch long would be tion of the pivots intheir'bearings, and the armature will not always come to rest in thesame position with the same current through the solenoid, which causesthe indications of the needle attached to the armature to be unreliable.However, I find that by providing a thin armature-for example, ofmaterial about one thirty-second of an inch thickwith enlarged polarsurfaces at the ends only, the attraction of the magnet upon the thinarmature is largely increased, so that the objections mentioned aboveare overcome. These three improvements are therefore important whentaken in conjunction with each other and with the other details, becausethe device may be manufactured more cheaply and yet with an improvedoutput, and, moreover, the reading is more-accurate and may be takenmore rapidly, and the instrument may be employed regardless ofsurrounding masses of iron or magnets. The shielding effect .is not theonly nor the most important object of the iron base-plate and theiron atthe end and top of the solenoid. The object of the iron base is fullyset forth in the former patent heretofore referred to.

Figure 1 is a plan taken from a full working device drawn to scale. Apart of the faceplate or cover is broken away. The important parts underthe faceqilate are represented by dotted lines. Fig. 2 isa view partlyin section and so taken as to best indicate the interior construction.Fig. 3 is an inverted plan of the main part of the face-plate, so as toshow the under side thereof. Fig. 4 is a diagram to illustrate theaction of the magnets upon the armature. Fig. 5 is a plan of thearmature in Fig. 4.. Figs. 6 and 7 are respective elevation and plan ofa different armature for the same purpose as in Figs. 4. and 5. Figs. 8and 9 are elevation and plan of a further modification. Fig. 10 is anend view of the iron plate 0, having a hole at its lower central portionfor the entrance of the small angle-iron O, which holds theelectromagnet to the base P by screws 0'.

The circuits for this instrument may be found described in said patent,but are not here described again, because they have nothing to do withthe novelty of the invention.

A is the permanent magnet of the meter.

B is the solenoid between the poles of the magnet A.

0 represents armatures for the magnet A, adjustable to and fro by meansof screws 1), passing through slots in the armature C. A part of thearmature for the solenoid and to which the needle E is attached is shownat F. Said armature is rotary about the pivot G through a sufficientlylong arc. At the end of the needle and under the same is a scale H,which may be seen through the hole I in the face-plate J, covered withglass K and havin, divisions longer and longer toward the right. Forevident reasons when a current is sent through the instrument the needleE oscillates back and forth, and after quite a long time it will come torest. To prevent these repeated oscillations, I provide a finger adaptedto be adjusted to substantially any portion of the path of the needle E.For this purpose the finger L is carried upon a thumbscrew M, whichturns in the face-plate J and is on the outside thereof, while thefinger L is on the inside.

N and N represent stops on the under side of the plate J, between whichthe finger L can be adjusted by means of the thumb-screw M. The fingeris bent at right angles to itself, one portion lying flat against theplate J and the other portion projecting therefrom.

The operation is as follows: Suppose each one of a number ofstorage-cells is to be tested and that each has an electromotive forceof abouttwovolts. Inthe ordinaryinstruments the pointer is at zero andafter connection is made with a cell swings from zero to a pointconsiderably beyond two volts, then returns toward zero, and continuesto move back and forth in lessening oscillations till it finally comesto rest at two volts. For example, the

pointer may move from 0 to 3.3, then back to 1, up to 3.0, back to 1.6,up to 2.2, back to 1.9, then to rest at two volts. By my device thethumb-screw M is turned so that the finger L pushes the needle till itpoints to 1.6 volts, for example, where it is allowed to rest. Theneedle E cannot move toward 0 on account of finger L, but is free tomove'in the opposite direction. When connection is made with a cell,referring to the example given above, the needle E will move from 1.6 to2.2, then return to 1.9, and then come to rest at two volts. The otheroscillations mentioned in the above example are thus omitted, and theneedle comes to rest proportionally quicker, probably saving more thanhalf the time.

The stop N is to limit the movement of the finger L, which otherwisemight push the needle beyond the scale and against the side of thevoltmeter-box, and thus bend or dam.- age the needle. The stop N is solocated as to prevent the needle from being pushed beyond 3.3 volts onthe scale and against the side of the box.

The supplementary shield O is a small angle-iron which extends over oneend of the solenoid, where it is attached to the iron baseplate P byscrews Q, and the other portion of the angle-iron extends over the topof the solenoid B on the side opposite the plate P, and it extendssubstantially the full length and width of said solenoid. Themathematics would be too complex for showing the exact dimensions ofthis shield for the best results; but the instructions given above whenfollowed are sufficiently approximate for practioal purposes.

R is a box in which the whole instrument is inclosed.

S represents lugs by which the plate P may be screwed to the box B.These lugs are not shown in Figs. 1 and 3, as they have no importance asto novelty.

Any other details not lettered or described have nothing to do with theinvention.

The shield 0 only has its valuable use when taken in conjunction withthe plate P; but as it has a proportional use without said plate Iintend that my invention includes said plate.

The iron plate P, permanent magnet A, solenoid B, and shield O are allwithin inductive action of one another, and the solenoid is between thepoles of the horseshoe-magnet A.

An essential feature of the invention is the armature for cooperatingwith the finger L and needle E and scale I for effecting the result ofaccurate and quick reading of the voltage. In Fig. 1 the armature is toosmall and too much hidden to be explained. By referring to certain otherfigures its construction may be made plain. The armature F consists of asmall and narrow plate of iron purposely having a maximum surface at acertain location of a certain shape and of a certain direction, but atthe same time as little mass as possible, so long as it has suificientmechanical strength and magnetic capacity. In Figs. at and 5 this objectis accomplished by providing bent-over ends F, which must face the polesand of the permanent magnet A when at rest in its normal position withno current passing through the electromagnet B. iVhenthe current isturned on, the electromagnet is energized-and the flanges F no longerface the permanent magnet, but gradually stand at a greater and greaterangle thereto, with the desired result that equal increments of currentproduce unequal and larger deflections of the armature F, and hence ofthe needle E. The explanation of this fact (determined by experiment) issupposed to be due to less and less surface of metal in the path of thelines of magnetic force from the permanent magnet; but the explanationis immaterial, for the fact remains the same. By means of the armaturein Figs. 6 and 7, where the ends F are bent backward nearly uponthemselves, with a space between, a similar result is obtained, and thisconstruction is employed when doflections are desired of less difierencein their lengths than those obtained by the armature shown in Figs. 4and 5. A similar result is obtained by the further extension of the endsto meet, forming a complete loop or oval, as in Figs. 8 and 9.

I claim as my invention-- I 1. In an electric meter, the combinationwith the solenoid thereof, of an iron plate covering two sides and oneend of said solenoid.

2. In an electric meter, the combination of apermanent magnet,asoleuoidwithininductive action thereof, a plate of iron on one side of saidelements and within inductive action thereof, a needle governed by saidsolenoid, and an angle-iron, whose portions are respectively at the endof said'solenoid andat that side which is opposite said plate.

3. In an electric meter, the combination of apermanent horseshoe-magnet,a solenoid between the poles thereof, a needle governed by saidsolenoid, and an iron plate shielding said solenoid on more than oneside thereof.

4. In an electric meter, the combination of an oscillating needle and aback stop finger L adjustable in the path of said needle and locatedentirely to one side of said needle.

5. In an electricmeter, the combination of a box R containing the same,a face-plate covering said box, an oscillating needle for the meter, abent finger having one portion adjacent to said plate and the otherportion extending to the path of said needle, a thumbscrew for turningsaid finger and located on the opposite side of said plate, and stopslying in the path of said finger. 4

6. In an electric meter, the combination of a containing-box, anoscillating needle for the meter, a finger for moving saidneedleforward, and a stop for limiting the forward movement of thefinger, and so located that the finger cannot push the needle againstthe side of the containing-box or other obstruction.

7. In an electric meter, the combination with. the permanent magnetthereof, of a pivoted armature between the poles of said magnet,consisting of a sheet of iron or steel with turned-over ends which facesaid poles, and

9. In an electric meter the combination with a permanent magnet, andwith the solenoid, of an armature to be actuated by said elements andconsisting of a plate of, iron so shaped that more surface faces thepoles of the magnet in the normal state of said armature, than whenturned to any abnormal position by the action of the solenoid.

10. In an electric meter, the combination with a permanent magnet, andwith the solenoid, of an armature to be actuated by said elements andconsisting of a plate of iron so shaped that more surface faces thepoles of the magnet in the normal state of said armature, than whenturned to any abnormal position by the action of the solenoid, anoscillating needle carried by said armature, and

anadjustable stop-finger and stop in the path of said needle.

11. In an electric meter, the combination of an indicating-scale, anoperating-needle, and a stop-finger adjustable in the path of saidneedle and located on the zero side of the needle.

12. The combination of a containing-box, a meter therein anindicating-scalefor the meter, a needle for the meter, a cover for thebox directly over the needle, and a stop-finger over said needle pivotedupon said coverv and having its free end portion bent downward into thepath of said needle, and a handle for said finger, and connectedtherewith andlocated on the other side of said cover from said finger.

the path of said needle, and a handle for said.

finger, and connected therewith and located "on the other side of saidcover from said finger, and stationary stops on opposite sides of saineedle and in the path thereof.

let. The combination of a containing-box, a meter therein, anindicating-scale for the .me-

ter, a needle for the meteiya cover for the boxdirectlyovertheneedle,andastop-fingerover venting it, at option, fromreturning to the 10 said needle pivoted upon said cover and havzero ofsaid scale. ing its free end portion bent downward into In testimonywhereof I hereunto sign my the path of said needle, and a handle forsaid name and affix my seal this 6th day of Sep- 5 finger, and connectedtherewith and located tember, 1901.

on the other side of said cover from said finger, LOUIS M. PIGNOLET. [L.3.] and stationary stops on opposite sides of said Witnesses: needle andin the path thereof, said finger be- A. O. BOUGHTON,

ing located to one side of the needle for prel t A. SMIETON.

